The present invention relates generally to a process which increases the available volume for a nutritive solution contained in a hydroponic receptacle into which at least one plant and one substratum have been placed.
A system known as hydroponics is used for the maintenance of plants under interior conditions: individual plants are placed into pots which are placed in turn into a receptacle; the space surrounding each individual pot is entirely filled with a substratum made up of light expanded clay granules; a nutritive solution occupies the bottom of the receptacle; the volume of this nutritive solution is limited by the volume of clay granules which occupy a considerable part of the total volume.
In order to promote the growing of the plants, the amount of the nutritive solution, already limited by the volume of clay granules, must not drop below a certain level. It is, therefore, necessary to replenish the water or nutritive solution within relatively short time intervals. Furthermore, the capillarity of the substratum favors the evaporation of water on the surface of the granules.
It has been shown through experiments that, given the height of the receptacle, the kind of plants used and the capillary properties of the substratum, the loss in liquid due to evaporation is six to ten times the amount of liquid needed by the plants for growth.
Should the hydroponic receptacle be exposed to the open air, the loss in liquid due to evaporation is exceedingly severe.
Attempts were made to increase the available volume for the nutritive solution by placing flower pots upside down on the bottom of the receptacle. This prevented the substratum from penetrating into the interior of the flowerpots and increased thereby the available volume for the nutritive solution. This attempt was only a limited success, as it was very difficult to distribute the upside down flowerpots, there was only little reduction of evaporation and, finally, the gain in volume was relatively small.
A further attempt to increase the available volume for a nutritive solution involved the use of a different substratum, namely synthetic pins; again, the attempt was only a limited success, as a large quantity of synthetic material was necessary, little reduction of evaporation occurred and the gain in volume was small.